Messages in this thread Patch in this message | | | Date | Thu, 28 Sep 2006 23:03:20 +0530 | From | Srivatsa Vaddagiri <> | Subject | [RFC, PATCH 8/9] CPU Controller V2 - task_cpu(p) needs to be correct always |
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We rely very much on task_cpu(p) to be correct at all times, so that we can correctly find the task_grp_rq from which the task has to be removed or added to.
There is however one place in the scheduler where this assumption of task_cpu(p) being correct is broken. This patch fixes that piece of code.
(Thanks to Balbir Singh for pointing this out to me)
Signed-off-by : Srivatsa Vaddagiri <vatsa@in.ibm.com>
---
linux-2.6.18-root/kernel/sched.c | 10 ++++++++-- 1 files changed, 8 insertions(+), 2 deletions(-)
diff -puN kernel/sched.c~cpu_ctlr_setcpu kernel/sched.c --- linux-2.6.18/kernel/sched.c~cpu_ctlr_setcpu 2006-09-28 16:40:37.844287616 +0530 +++ linux-2.6.18-root/kernel/sched.c 2006-09-28 17:23:14.896556584 +0530 @@ -5230,6 +5230,7 @@ static int __migrate_task(struct task_st { struct rq *rq_dest, *rq_src; int ret = 0; + struct prio_array *array; if (unlikely(cpu_is_offline(dest_cpu))) return ret; @@ -5245,8 +5246,8 @@ static int __migrate_task(struct task_st if (!cpu_isset(dest_cpu, p->cpus_allowed)) goto out; - set_task_cpu(p, dest_cpu); - if (p->array) { + array = p->array; + if (array) { /* * Sync timestamp with rq_dest's before activating. * The same thing could be achieved by doing this step @@ -5256,6 +5257,11 @@ static int __migrate_task(struct task_st p->timestamp = p->timestamp - rq_src->timestamp_last_tick + rq_dest->timestamp_last_tick; deactivate_task(p, rq_src); + } + + set_task_cpu(p, dest_cpu); + + if (array) { __activate_task(p, rq_dest); if (TASK_PREEMPTS_CURR(p, rq_dest)) resched_task(rq_dest->curr); _ -- Regards, vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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